CN109495818B

CN109495818B - Vibrating diaphragm

Info

Publication number: CN109495818B
Application number: CN201811309328.6A
Authority: CN
Inventors: 王婷; 王伟超; 李春
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2018-11-05
Filing date: 2018-11-05
Publication date: 2021-12-28
Anticipated expiration: 2038-11-05
Also published as: CN109495818A

Abstract

The invention discloses a vibrating diaphragm. The diaphragm includes an elastomeric layer. The method of making the elastomeric layer comprises: adding nano silicon dioxide into an organic solvent and performing dispersion treatment to form a first mixed liquid; mixing a polyol, the organic solvent, and a catalyst to form a second mixed liquid; mixing the first mixed liquid and the second mixed liquid to form a third mixed liquid; adding polyisocyanate into the third mixed liquid and uniformly mixing; adding a chain extender into the third mixed liquid after the polyisocyanate is added, and uniformly mixing to form a polymer solution; and solidifying the polymer solution.

Description

Vibrating diaphragm

Technical Field

The invention relates to the technical field of electroacoustic conversion, in particular to a vibrating diaphragm.

Background

In the conventional speaker, the diaphragm mostly adopts a single-layer or multi-layer composite structure of a high-modulus plastic substrate layer (e.g., PEEK, PAR, PEI, PI, etc.), a conventional elastomer material layer (e.g., silicone rubber, TPU, TPEE, TPS, etc.), and a damping adhesive layer (e.g., acrylic adhesive, silicone adhesive, etc.). With the increasing demands for ultra-thinness, high power, water resistance, and high sound quality of speakers, higher demands have been made on the thickness, resilience, temperature resistance, and the like of diaphragms for speakers.

When the plastic substrate layer is used as a support material of the vibrating diaphragm, the material is in a glass state at room temperature, and the chain segment cannot move, so that the resilience and the damping property of the material are insufficient. When the composite film adopting the plastic substrate layer is used as the vibrating diaphragm, the problems of cracking, damage, collapse and the like of the vibrating diaphragm are easy to occur after long-time electrification, and the requirement of the current high waterproof grade cannot be met.

The modulus or hardness of silicone rubber is relatively low. When the diaphragm is used as a substrate layer, the thickness of the diaphragm is thicker under the condition of meeting the same F0 requirement. Thus, on the one hand, the margin of the vibration space is reduced, and on the other hand, the mass of the vibration system is increased, and the sensitivity is lowered.

The hardness and resilience of the conventional thermoplastic elastomer material are difficult to be considered. In order to realize the ultra-thinness of the speaker, the diaphragm is required to be thin. To achieve the desired F0, an elastomeric material with a high hardness needs to be selected. However, the increase in hardness results in a reduction in the resilience of the material and a reduction in the level of waterproofing of the speaker.

Therefore, a new technical solution is needed to solve the above technical problems.

Disclosure of Invention

One object of the present invention is to provide a new technical solution for a diaphragm.

According to a first aspect of the invention, a diaphragm is provided. The diaphragm comprises an elastomer layer, and the preparation method of the elastomer layer comprises the following steps: adding nano silicon dioxide into an organic solvent and performing dispersion treatment to form a first mixed liquid; mixing a polyol, the organic solvent, and a catalyst to form a second mixed liquid; mixing the first mixed liquid and the second mixed liquid to form a third mixed liquid; adding polyisocyanate into the third mixed liquid and uniformly mixing; adding a chain extender into the third mixed liquid after the polyisocyanate is added, and uniformly mixing to form a polymer solution; and solidifying the polymer solution.

Optionally, the polyol comprises at least one of a polyether polyol and a polyester polyol.

Optionally, the organic solvent includes at least one of a ketone organic substance, an ester organic substance, an ether organic substance, an amide organic substance, a hydrocarbon organic substance, and a silane coupling agent organic substance.

Optionally, the polyisocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicycloethyl methane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

Alternatively, the molar ratio of-NCO groups of the polyisocyanate to-OH groups of the polyol is from 2 to 2.5.

Optionally, the chain extender comprises a compound containing a plurality of hydroxyl groups and/or a compound containing a plurality of amino groups.

Optionally, the catalyst comprises at least one of an amine-based catalyst and an organometallic-based catalyst.

Optionally, the mass content of the nano silica in the polymer solution is 1-25%.

Optionally, the elastomer layer has a thickness of 5-100 μm.

Optionally, in the step of mixing the polyol, the organic solvent and the catalyst to form a second mixed liquid, the heating temperature is 60-80 ℃ and the heating is performed under the protection of nitrogen or inert gas; the heating temperature at the time of curing is 60 to 160 ℃.

Optionally, the elastomeric layer has a glass transition temperature of from-10 to-75 ℃ and a flow temperature of greater than or equal to 180 ℃.

According to one embodiment of the disclosure, the diaphragm has the characteristics of excellent resilience, rigidity and temperature resistance.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1-5 are cross-sectional views of diaphragms in accordance with embodiments of the invention.

Description of reference numerals:

11: an elastomeric layer; 12: a damping glue layer; 13: and a plastic substrate layer.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

According to one embodiment of the present disclosure, a diaphragm is provided. The vibrating diaphragm is used for a sound generating device. The vibrating diaphragm is of a corrugated ring structure or a plane structure.

Wherein the diaphragm comprises an elastomer layer 11. For example, the diaphragm includes a plurality of membrane layers. At least one of the film layers is the elastomer layer 11; or the diaphragm is a single-layer film. The elastomer layer 11 forms a diaphragm.

The method of making the elastomeric layer 11 comprises:

s1, adding the nano-silica into the organic solvent and performing a dispersion process to form a first mixed liquid.

Wherein the organic solvent comprises at least one of ketone organic matter, ester organic matter, ether organic matter, amide organic matter, hydrocarbon organic matter and silane coupling agent organic matter. The organic solvent has low viscosity, and is convenient for dispersing the nano silicon dioxide.

Preferably, the organic solvent includes at least two of the above-mentioned organic substances. Different kinds of organic matters can more effectively disperse the nano silicon dioxide.

The purpose of the dispersion treatment is to uniformly mix the nanosilica with the organic solvent. For example, the dispersion treatment is performed using a dispersion apparatus such as an ultrasonic disperser, a high-speed disperser, or a high-speed shear disperser. The treatment time is 0.5-1.5 hours. Because the particle size of the nano silicon dioxide is small, the nano silicon dioxide is added into the polyurethane solution in a direct blending mode and is easy to agglomerate. The nano silicon dioxide is agglomerated into micron-sized particles, thereby losing the unique modification capability of the nano material. The dispersing equipment can effectively disperse the nano silicon dioxide, and reduces the agglomeration phenomenon.

In this step, the nano-silica is thoroughly mixed with the organic solvent using a dispersing apparatus. In some solvents, for example, solvents containing silane coupling agents, the silane coupling agents are capable of coupling with the siloxane bonds of the nanosilica. Thus, the driving force of the coupling reaction enables the nano-silica to be more effectively dispersed in the first organic liquid, and the agglomeration phenomenon can be more effectively prevented, so that the modification effect of the nano-material is more excellent, and the rigidity, resilience and temperature resistance of the obtained elastomer layer 11 are more excellent.

S2, mixing the polyol, the organic solvent and the catalyst to form a second mixed liquid.

Specifically, the polyhydric alcohol refers to an alcohol having two or more hydroxyl groups in the molecule. For example, the polyol may be, but is not limited to, at least one of a fatty polyol and a rigid polyol.

Wherein the aliphatic polyol comprises polyether polyol and polyester polyol. Polyether polyols include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetrahydrofuran ether, and the like. The polyester polyol comprises polycaprolactone polyol, polyethylene glycol adipate glycol, polyethylene glycol-propylene glycol adipate, polyethylene glycol diglycol adipate glycol, polybutylene adipate-1, 4-butylene glycol adipate, neopentyl glycol adipate-1, 6-hexanediol adipate, polyethylene castor oil ester polyol, poly-e-caprolactone glycol and polycarbonate-1, 6-hexanediol adipate.

Rigid polyol refers to a polyol containing rigid groups. For example, the rigid group includes a benzene ring or a phenol group.

The polyol may be a mixture of one or more of the above-mentioned various organic substances.

The organic solvent is as described above. The organic solvent can be uniformly mixed with the polyol and the catalyst.

The catalyst is used to catalyze the polymerization reaction. For example, the catalyst includes an amine catalyst or an organometallic catalyst, and the like.

Wherein the amine catalyst comprises N, N-dimethylcyclohexylamine, N-ethylmorpholine, triethanolamine, DMEA, pyridine and the like. Organometallic catalysts include dibutyl tin dilaurate, hydroxy acid salts, metal alkyl compounds, and the like.

The catalyst may be a mixture of one or more of the above-mentioned various catalysts. The catalytic effect of different catalysts is different. The kind of the catalyst may be selected according to the kind of the reactant.

In one example, the various species in step S2 are under nitrogen N₂Or other inert gas, and mixing under heating. For example, the heating temperature is 60 to 80 ℃. Nitrogen or other inert gas is kept introduced during the mixing process. The heating temperature can keep the viscosity of various substances to be small, the substances have good fluidity and are easy to mix uniformly, and the reaction can not be carried out too fast at the temperature and is easy to control the reaction heat. N is a radical of₂Or the inert gas condition can reduce the humidity of the mixing environment, prevent moisture from entering, and can prevent various substances from being oxidized.

It should be noted that the step S1 and the step S2 are not in sequence. The two steps may be performed simultaneously; it is also possible to perform one of the steps first and then the next.

And S3, mixing the first mixed liquid and the second mixed liquid to form a third mixed liquid.

In this step, mixing may be performed using the above-mentioned dispersing apparatus, for example, a dispersing treatment may be performed at a temperature of 60 to 80 ℃ for 0.5 to 3 hours so that the nano-silica can be uniformly dispersed in the system.

And S4, adding the polyisocyanate into the third mixed liquid, and uniformly mixing.

For example, the reaction is stirred at a high speed for 1 to 3 hours using the above-mentioned dispersing apparatus. The high-speed stirring enables efficient heat dissipation, which enables the reaction to proceed more smoothly.

Wherein the polyisocyanate comprises at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicycloethyl methane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.

Under the action of a catalyst, polyisocyanate, polyol and nano-silica are subjected to polymerization reaction to form short-chain prepolymer.

Preferably, the amounts of the various substances added are controlled so that the molar ratio of-NCO groups of the polyisocyanate to-OH groups of the polyol is from 2 to 2.5. The good homogeneity of the prepolymer within this ratio ensures that the finally prepared elastomer layer 11 has a higher molecular weight, thereby ensuring that the elastomer layer 11 has good strength and resilience.

It is to be noted that the polyisocyanate is easily reacted with water to form amine and CO₂Therefore, various organic materials used in the steps S1 and S2 are first dehydrated. For example, dehydration is performed by distillation using a difference in boiling point between various organic materials.

In addition, the introduction of nitrogen gas in each step of preparing the elastomer layer 11 also prevents moisture in the air from entering the reaction system and affecting the progress of the polymerization reaction.

And S5, adding a chain extender into the third mixed liquid after the polyisocyanate is added, and uniformly mixing to form a polymer solution.

Specifically, the chain extender enables the reaction system to carry out chain extension reaction. The chain extender links together short-chain prepolymers to form long-chain polymers, increasing the degree of polymerization of the polymer. In the step, high-speed stirring reaction is continuously carried out for 1-3 hours, and finally, the polymer solution of the carbamate-nano silicon dioxide is prepared.

Wherein the chain extender comprises a compound containing a plurality of hydroxyl groups and/or a compound containing a plurality of amino groups. For example, chain extenders include ethylene glycol, glycerol, 1, 4-butanediol, ethylenediamine, MOCA, 1, 4-cyclohexanediol, hydrogenated bisphenol a, dimethylene phenyl diol, hydroquinone bis-beta-hydroxyethyl ether, resorcinol hydroxy ether, glycidyl allyl ether, dicumyl peroxide, and the like; sulfur can also be used as a chain extender. Both the plurality of hydroxyl groups and the plurality of amino groups are capable of coupling to the prepolymer, thereby changing the short chain to a long chain.

S6, the polymer solution is cured to form the elastomer layer 11.

Specifically, the elastomer layer 11 is a polyurethane material modified with nano silica. For example, a polymer solution is coated to obtain a material with a desired thickness, and then placed in an oven for heat curing. The oven temperature ranges from 60 ℃ to 160 ℃. In this step, on one hand, the organic solvent in the polymer solution is volatilized to form a thin film, and on the other hand, the molecular chain segments of the polymer solution are further crosslinked and cured, so that the structure and strength of the elastomer layer 11 are improved. The film can be cut into a set shape according to actual needs.

The thickness of the elastomer layer 11 is, for example, 5 to 100 μm. This thickness range provides the diaphragm with sufficient stiffness, resilience and damping properties and provides a greater spatial margin for the vibrating system.

For example, the glass transition temperature of the elastomeric layer 11 is from-10 to-75 ℃. The above properties indicate that the elastomer layer 11 is excellent in low temperature resistance. The elastomer layer 11 is in a highly elastic state at room temperature, and exhibits excellent elasticity. A flow temperature of 180 ℃ or higher, wherein the flow temperature is a temperature at which the tensile modulus is 1 MPa. This indicates that the elastomer layer 11 has excellent high temperature resistance.

In one example, the nanosilica is present in the polymer solution in an amount of 1-25% by mass. The nano silicon dioxide in the range can effectively modify the elastomer layer 11 of the polyurethane material, and improve the performances of the elastomer layer 11 such as rebound resilience, rigidity, temperature resistance and the like.

In one example, the diaphragm further includes a plastic substrate layer 13 and a damping adhesive layer 12. The elastomer layer 11 is laminated with the plastic substrate layer 13 and the damping glue layer 12. The damping glue layer 12 is self-adhesive and can be directly bonded to the plastic substrate layer 13 or the elastomer layer 11. The number of layers and the combination of the elastomer layer 11, the plastic base layer 13, and the damping rubber layer 12 are not limited herein. The composite material diaphragm has the characteristics of various materials, so that the comprehensive performance of the diaphragm is more superior.

Fig. 1 shows a diaphragm of a single-layer film structure. In this example, the diaphragm comprises only one elastomer layer 11.

Fig. 2 shows a diaphragm of a two-layer membrane structure. In this example, the diaphragm includes an elastomer layer 11 and a plastic substrate layer 13 that are laminated together. The elastomer layer 11 and the plastic substrate layer 13 are bonded together by heat bonding. The plastic base layer 13 includes any one of polyether ether ketone (PEEK), Polyarylate (PAR), Polyetherimide (PEI), Polyimide (PI), polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and the like. The plastic substrate layer 13 made of the material has high rigidity, so that the diaphragm has good durability.

Fig. 3 shows a diaphragm of a three-layer membrane structure. In this example, the diaphragm comprises two elastomer layers 11 and one damping glue layer 12, which are compounded together. The damping rubber layer 12 has adhesive property. The two elastomer layers 11 are respectively positioned on the upper surface and the lower surface of the damping rubber layer 12. The damping glue layer 12 is one or more of acrylic damping glue, silicone damping glue, epoxy damping glue, polyurethane damping glue, and the like. The damping glue layer made of the material has good damping effect and can effectively absorb noise generated when the vibration system vibrates.

Fig. 4 shows a diaphragm of another three-layer membrane structure. In this example, the diaphragm includes an elastomer layer 11, a damping glue layer 12, and a plastic substrate layer 13, which are laminated together. The elastomer layer 11 and the plastic substrate layer 13 are respectively positioned on the upper surface and the lower surface of the damping glue layer 12 and directly bonded with the damping glue layer 12. The plastic substrate layer 13 and the damping rubber layer 12 are made of the materials as described above.

Fig. 5 shows a diaphragm of a five-layer membrane structure. In this example, the diaphragm includes two elastomer layers 11, two damping adhesive layers 12, and one plastic substrate layer 13, which are laminated together. The two damping glue layers 12 are respectively bonded on the upper surface and the lower surface of the plastic base material layer 13. The two elastomer layers 11 are used as an upper surface layer and a lower surface layer and are respectively bonded on the outer sides of the two damping rubber layers 12. The plastic substrate layer 13 and the damping rubber layer 12 are made of the materials as described above.

The vibrating diaphragm has good rebound resilience, rigidity, temperature resistance and the like.

Of course, the structure of the diaphragm is not limited to the above-mentioned embodiments, and those skilled in the art can select the diaphragm according to actual needs.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A diaphragm comprising an elastomer layer, the preparation method of the elastomer layer comprising:

adding nano silicon dioxide into an organic solvent and carrying out dispersion treatment to form a first mixed liquid, wherein the dispersion treatment time is 0.5-1.5 hours;

mixing a polyol, the organic solvent, and a catalyst to form a second mixed liquid; under the condition of nitrogen or other inert gases, the second mixed liquid is mixed under the heating condition, and the heating temperature is 60-80 ℃;

mixing the first mixed liquid and the second mixed liquid to form a third mixed liquid; performing dispersion treatment at 60-80 deg.C for 0.5-3 hr;

adding polyisocyanate into the third mixed liquid and uniformly mixing, wherein the molar ratio of-NCO groups of the polyisocyanate to-OH groups of the polyol is 2-2.5;

adding a chain extender into the third mixed liquid after the polyisocyanate is added, and uniformly mixing to form a polymer solution;

solidifying the polymer solution;

wherein the thickness of the elastomer layer is 5-100 μm;

the organic solvent comprises ketone organic matters, ester organic matters, ether organic matters, amide organic matters, hydrocarbon organic matters and silane coupling agent organic matters; the organic solvent adopted in the first mixed liquid is at least two organic matters, and the organic solvent in the second mixed liquid is at least one organic matter.

2. The diaphragm of claim 1, wherein the polyol includes at least one of polyether polyol and polyester polyol.

3. The diaphragm of claim 1, wherein the polyisocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

4. The diaphragm of claim 1, wherein the chain extender comprises a compound containing a plurality of hydroxyl groups and/or a compound containing a plurality of amino groups.

5. The diaphragm of claim 1, wherein the catalyst includes at least one of an amine-based catalyst and an organometallic-based catalyst.

6. The diaphragm of claim 1, wherein the nano-silica is present in the polymer solution in an amount of 1-25% by mass.

7. The diaphragm of claim 1, wherein in the step of mixing the polyol, the organic solvent and the catalyst to form the second mixed liquid, the heating temperature is 60-80 ℃ and is performed under the protection of nitrogen or inert gas;

the heating temperature at the time of curing is 60 to 160 ℃.

8. The diaphragm of claim 1, wherein the elastomer layer has a glass transition temperature of-10 to-75 ℃ and a flow temperature of greater than or equal to 180 ℃.